[Python-Dev] Comparison speed (original) (raw)

Martin v. Loewis martin@loewis.home.cs.tu-berlin.de
Mon, 14 May 2001 23:55:39 +0200

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Anybody care to take a stab at making the new richcmp and/or coerce code ugly again?

Hi Tim,

With CVS Python, 1000000 iterations, and a for loop, I currently got

0.780 0.770 0.770 0.780 0.770 0.770 0.770 0.780 0.770 0.770

With the patch below, I get

0.720 0.710 0.710 0.720 0.710 0.710 0.710 0.720 0.710 0.710

The idea is to let strings support richcmp; this also allows some optimization for the EQ case.

Please let me know what you think.

Martin

Index: stringobject.c

RCS file: /cvsroot/python/python/dist/src/Objects/stringobject.c,v retrieving revision 2.115 diff -u -r2.115 stringobject.c --- stringobject.c 2001/05/10 00:32:57 2.115 +++ stringobject.c 2001/05/14 21:36:36 @@ -596,6 +596,51 @@ return (len_a < len_b) ? -1 : (len_a > len_b) ? 1 : 0; }

+/* In the signature, only a is guaranteed to be a PyStringObject.

However, as the first thing in the function, we check that b
is of that type also. */
+static PyObject* +string_richcompare(PyStringObject *a, PyStringObject *b, int op) +{
int c;
PyObject *result;
if (!PyString_Check(b)) {
```
  result = Py_NotImplemented;
```
```
  goto out;
```
}
if (op == Py_EQ) {
```
  if (a->ob_size != b->ob_size) {
```
```
     result = Py_False;
```
```
     goto out;
```
```
  }
```

+#ifdef CACHE_HASH + if (a->ob_shash != b->ob_shash + && a->ob_shash != -1 + && b->ob_shash != -1) { + result = Py_False; + goto out; + } +#endif + } + c = string_compare(a, b); + switch (op) { + case Py_LT: c = c < 0; break; + case Py_LE: c = c <= 0; break; + case Py_EQ: c = c == 0; break; + case Py_NE: c = c != 0; break; + case Py_GT: c = c > 0; break; + case Py_GE: c = c >= 0; break; + default: + result = Py_NotImplemented; + goto out; + } + result = c ? Py_True : Py_False;

out:
Py_INCREF(result);
return result; +}
static long string_hash(PyStringObject *a) { @@ -2409,6 +2454,12 @@ &string_as_buffer, /tp_as_buffer/ Py_TPFLAGS_DEFAULT, /tp_flags/ 0, /tp_doc/
0, /tp_traverse/
0, /tp_clear/
(richcmpfunc)string_richcompare, /tp_richcompare/
0, /tp_weaklistoffset/
0, /tp_iter/
0, /tp_iternext/ };

void

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